A new research analysis has found that one of the important reasons behind the high number of measles cases, which has recently triggered an outbreak across the United States, was the low rate of vaccination in the country.

For the study, the scientists used complex mathematical models so as to find out the account for the rapid spread of the virus among the visitors of Disneyland.

The researchers at Boston Children’s Hospital collected and analyzed the measles case numbers reported by the California Department of Public Health and other regional surveillance records in order to find estimates of the vaccination rates of areas hit by the outbreak in Arizona, California and Illinois.

The measles outbreak, which has been traced to Disneyland in California in December last year, mainly affected those who were likely vaccinated at substandard rates.

Maimuna Majumder, lead study author and a research fellow at Boston Children’s Hospital, said, “Substandard vaccination means that less than 96 to 99 percent of the population exposed to measles during the course of the outbreak were vaccinated.”

During the study, the researchers found that the worst-hit areas showed vaccination rates as low as 50 percent. This conveniently allowed the rapid spread of the disease across the country, the research suggested.

Underscoring the findings of the analysis, Majumder said, “In our study, we discovered that MMR vaccination rates among the exposed population during the outbreak is likely to be as low as 50 percent and may be no higher than 86 percent.”

According to the researchers, the only statistically viable explanation for the high rate of proliferation of the potentially fatal virus is the large number of under-vaccinated children across the United States.

Nearly 133 cases of measles infections have been reported from across eight states in the US since the outbreak emerged in Southern California’s Disney Park late last year.

The researchers also cautioned against the ongoing outbreak in their concluding remarks, saying “it shines a glaring spotlight on the growing anti-vaccination movement in our nation and the prevalence of vaccination-hesitant parents.”

A large number of parents are opting out against vaccinating their children against serious ailments owing to their religious or personal beliefs.

About 93 percent of kids are administered with proper vaccination against the infectious measles virus. But the anti-vaccination movement in the country has fueled a large number of parents to deny vaccination for their children.

The number of unvaccinated kids has been growing in recent years. The more concerning thing is that even 92 percent vaccinated kids fail to prevent the spread of the highly contagious measles virus.

Some of the common symptoms of measles are high fever, runny nose and cough, usually followed by red rashes on the skin, starting first on the face and gradually spreading over the entire body.

The detailed findings of the study were published this week in the journal JAMA.